Answer this question truthfully
### Question: What causes Transient ischemic attack?
### Response: A transient ischemic attack (TIA) is caused by temporary disturbance of blood supply to an area of the brain. This results in a sudden, brief decrease in brain function. (A decrease in brain function is called a neurologic deficit.)
A TIA is different from a stroke. Unlike a stroke, a TIA does not cause brain tissue to die. The symptoms of TIAs do not last as long the symptoms of a stroke. TIAs also do not show changes to the brain on CT or MRI scans. (Strokes usually show changes on such tests.)
The temporary loss of blood flow to the brain can be caused by:
A blood clot within an artery of the brain A blood clot that travels to the brain from somewhere else in the body (for example, the heart) An injury to blood vessels Narrowing of a blood vessel in the brain or leading to the brain
For instance, the temporary disruption in blood flow could be due to a blood clot that occurs and then dissolves. The blockage breaks up quickly and dissolves.
Less common causes of TIA include:
An irregular heart rhythm called atrial fibrillation Certain blood disorders, including polycythemia, sickle cell anemia, and syndromes where the blood is very thick Conditions that cause blood vessels problems such as fibromuscular dysplasia, systemic lupus erythematosus, and syphilis Inflammation of the arteries such as arteritis, polyarteritis, and granulomatous angiitis Spasm of the small arteries in the brain
Atherosclerosis ("hardening of the arteries") is a condition where fatty deposits occur on the inner lining of the arteries. This condition dramatically increases the risk for both TIAs and stroke. About 80 - 90% of people who have a stroke due to atherosclerosis had a TIA episode before.